The protection of vehicle occupants in the case of an accident by deploying irreversible restraining means (airbags in particular) is nowadays standard, the irreversible restraining means being pyrotechnically ignited when an impact is detected by acceleration sensors in particular.
In addition, it has also become customary to investigate, even prior to the actual impact, whether there is an imminent risk of such an impact. As a function thereof, the irreversible restraining means are set to a state of readiness to very quickly enable the actual deployment when the impact is detected. Furthermore, reversible restraining means, power safety belt tensioners in particular, are activated to forcibly move the affected occupants into the best possible position in the seat. This is briefly explained below with reference to FIG. 5. FIG. 5 shows two vehicles 21 and 22, which move toward one another at velocities V1 and V2, respectively. While vehicle 21 is traveling on its proper right side of the road 23, second vehicle 22 has left its proper right side of the road 24. This means that there is a latent risk of collision between vehicles 21 and 22. In any case, when the distance between the two vehicles 21 and 22 traveling at a certain relative velocity (V1+V2) drops below a certain distance, i.e., the time to impact (time=distance/relative velocity)drops below a certain time, a collision must be considered as unavoidable. When such a situation is detected, the above-mentioned preventive measures are initiated.
This procedure is basically also applicable if a single vehicle moves toward a stationary obstacle, i.e., object. Also in this case, an analyzer circuit of the vehicle will use the relative velocity with respect to the object and the distance to the object to evaluate whether or not a collision is imminent.
The conventional modes of operation thus assume the actual occurrence of a collision (crash) or the detection of an imminent, unavoidable collision.
However, the known procedures do not allow for a response to events in which the vehicle gradually approaches an object such as a guardrail, a wall, stationary, parked or slowly moving vehicles, or the like. Forces which may result in injuries, due to impact with vehicle parts in particular, may act upon vehicle occupants, unaware occupants in particular, even in the event of such a grazing contact.
An object of the present invention is therefore to provide a method and a system to effectively protect vehicle occupants even in non-impact danger situations.